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Xuan Lin

Publications and source records attributed to Xuan Lin.

4 recordsLinked to original sources
PubMed2006

Determination of trace lead by solid substrate room temperature phosphorescence enhancing method based on heavy atom effect and dissoluble manganese supramolecule containing rhodamine 6G luminescent particles.

Dissoluble manganese supramolecule containing rhodamine 6G luminescent particles (M2) are synthesized, based on dissoluble manganese supramolecule (M1) doping rhodamine 6G (R.6G), by crystalline method. The particle diameters of M1 and M2 determined by ETM are both of micron degree. M1 and M2 can emit solid substrate room temperature phosphorescence (SS-RTP) on filter paper. The transition probability from the singlet state (S1) to triplet state (T1) of the luminescent molecules was greatly enhanced, based on the increment of luminescent molecules for each spot and the heavy atom effect of certain amount of Pb2+. As a result, the phosphorescence intensity (Ip) of M2 was increased sharply, and the enhancing value of phosphorescence intensity (DeltaIp) is directly proportional to the concentration of Pb2+. Thus, a new method of SS-RTP enhancing for the determination of trace lead is established based on manganese supramolecule containing rhodamine 6G luminescent particles. The linear range of this method is 0.0040-0.400 pg spot-1 of Pb2+ (corresponding concentration, 0.01-1.0 ng mL-1; sample volume, 0.4 microL spot-1), with a detection limit (LD) of 0.0011 pg spot-1 (corresponding concentration, 2.8x10(-12) g mL-1 of Pb2+, n=11). For the working solutions containing 0.0040 and 0.40 ng mL-1 of Pb2+, they were determined repeatedly for seven times, respectively. The R.S.D.s were 3.2 and 3.8%, respectively. This method has good repeatability, sensitivity and high precision. It has been applied to the determination of trace lead in human hair and tea samples with satisfactory results.

Cations, Divalent↗
PubMed2006

[Effects of allelopathic rice on rhizosphere microbial flora and enzyme activity].

This paper studied the dynamics of microbial flora and enzyme activity in the rhizosphere of allelopathic rice PI312777 (PI) and non-allelopathic rice Lemont (LE) at the growth stage of 3 - 7 leaves. The results showed that in the rhizosphere of PI, the amounts of bacteria, actinomycetes and azotobacter were 11.2% - 28.3%, 40% - 78.6% and 111.5% - 173.9%, respectively, while that of fungi was lower, with the maximum being 25.5% of that in the rhizosphere of LE, suggesting that allelopathic rice PI promoted the growth of bacteria, actinomycetes and azotobacter, but inhibited that of fungi. Further analysis on the physiological groups of microbial flora showed that PI favored the growth of ammonifier, aerobic azotobacter, aerobic cellulose - decomposer, sulphate - reducer, nitrite - bacteria and nitrate - bacteria, among which, ammonifier and aerobic azotobacter increased by 53.7% and 57.6%, respectively, while inhibited the growth of desulphate bacteria and denitrifyier. Moreover, PI increased the activities of urease, phosphatase and sucrase, but decreased the catalase activity in its rhizosphere.

Actinobacteria↗
PubMed2005

Determination of trace copper by solid substrate-room temperature phosphorescence quenching method based on activating effect of alpha,alpha'-dipyridyl on Vitamin C reducing beryllon.

A new solid substrate-room temperature phosphorescence quenching method for the determination of trace copper has been established. It is based on the fact that beryllon (R) can emit strong and stable solid substrate-room temperature phosphorescence on the filter paper, and Vitamin C (Vc) reduces R to non-phosphorescent compound that leads to solid substrate-room temperature phosphorescence (SS-RTP) quenching of R, and alpha,alpha'-dipyridyl can activate copper catalyzing Vitamin C reducing R. The DeltaI(p) of the system with alpha,alpha'-dipyridyl is 3.3 times higher than that without alpha,alpha'-dipyridyl, which shows the reaction of alpha,alpha'-dipyridyl activating copper catalyzing Vitamin C reducing R. The reducing value of phosphorescence intensity (DeltaI(p)) is directly proportional to the content of Cu(II) in the range of 0.040-4.0 fg spot(-1) (corresponding concentration: 0.10-10.0 pg ml(-1), sample volume: 0.40 microlspot(-1)). The regression equation of working curve can be expressed as DeltaI(p)=69.99+41.00 m Cu(2+) (fg spot(-1)) (r=0.9980, n=6), and the detection limit is 0.0088 fg spot(-1)(corresponding concentration: 2.2 x 10(-14) g ml(-1)). This sensitive and accurate method with good repeatability and high selectivity has been applied to the determination of trace copper in real samples with satisfactory results. The reaction mechanism for the determination of trace copper by solid substrate-room temperature phosphorescence quenching method based on the activating effect of alpha,alpha'-dipyridyl on Vitamin C reducing beryllon is also discussed.

Ascorbic Acid↗